They were not the only ones, see PTC, Aicas, IBM, and a few others.

The big difference until GraalVM and OpenJ9 became available as open source, was that all those vendors made AOT compilation a commercial feature, and thus most devs never cared they existed.

In fact GraalVM was one of the main reasons Excelsior JET eventually closed doors.

Don't forget GCJ. It wasn't removed from GCC until about 2016, a nearly 20-year long run, though interest had waned many years prior.

I don't remember if GCJ supported loading and running code dynamically with a built-in JIT or interpreter. I think it was just pure AOT, which caused some compatibility headaches.

IBM's J9 had AOT for a long time too. I wonder how JEP 544 compares.